How to Build a Simple Greenhouse

By | January 21, 2014

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Options, Options, Options

Greenhouses are one of the most versatile and beneficial structures to add to your farm or urban homestead. You can even build simple greenhouse options for your apartment balcony with a few pieces of wood and an old window. All you need is a sturdy frame and a way to let in plenty of sunlight while controlling inside temperature, humidity, and airflow.

Greenhouses can be built in a hoop style with nothing more than PVC piping, a few pieces of lumber, and some 6 mil plastic sheeting. Hoop houses are perfect structures for temporary storage of weather-sensitive plants or in areas where snow and high winds are not a factor. You can even build indoor greenhouses, if you are really tight on space. For the industrious builders who want a larger greenhouse, or those who need to consider severe weather factors, a wood or metal frame greenhouse with heavy gauge double wall plastic is better. You can also use old reclaimed windows and doors instead of plastic sheeting.

Start Simple and Experiment

If this is your first foray into greenhouse building, simplicity is often best. To build a simple greenhouse, you usually only need basic carpentry skills and relatively inexpensive building supplies. You can experiment as you gain more experience. The following plans are intended to provide a sturdy structure for nearly any climate, use as much reclaimed material as possible, and provide easy ventilation.

For this build, you will need the following major materials:

  • A long pole or 2×4 for measuring
  • Several lengths of 2x4s (reclaimed wood is well-aged, and therefore well suited for such structures, especially redwood)
  • One 2×6 the length of your planned greenhouse
  • 6 mil or heavier plastic sheeting
  • As many reclaimed doors and windows as you can find
  • Wood lathe strips or other small, thin strips of wood
  • Galvanized Hurricane ties (found at your local hardware store, used to secure roof rafters to beams)
  • Galvanized Framing angles (usually found in the same isle as hurricane ties)
  • Weather resistant glue
  • Galvanized screws and nails
  • Weather resistant outdoor caulking
  • Staples and staple gun
  • Heavy gauge baling or barbless wire (optional)
  • Old reclaimed rain gutters (optional)
  • Circular saw
  • Drill
  • Measuring tape

Determine the Size for Your A Frame

A frame structures are some of the easiest structures for the novice to build. There are no complicated trusses, roof pitches, or angle computations to consider. All you need to know is how much floor space and headroom you need. Since the roof and walls form an “A,” you will need to consider the slope in your height and floor space requirements, but this isn’t difficult. All you need is a measuring tape and a long 2×4 or pole.

Start by deciding how much growing floor space you need. Presumably, you will want enough room for planting beds 2-4 feet wide on either sidewall, with a walkway in the middle of at least 3 feet. That means 10 feet or more for your width. Adding length to your design provides more space, if needed. Mark out one line equal to the width of your floor space. You can do this with garden stakes.

Stand in the exact center of your marked line with your 2×4 or pole. Mark a comfortable stand up height on your pole. This should be a least a foot taller than the tallest person who will be using the greenhouse. Have a helper hold the pole or 2×4 while you measure from the mark on the pole to either end of your marked line. This gives you the length of either side of your “A.” You will need to cut your lumber for the side frames to this length later, but for now, it just helps you determine how much lumber you will need.

Continue to Page 2 for Foundation and Framing Instructions

Plans to Build Simple Greenhouse, Page 2Continuing the instructions on how to build simple greenhouse structures, issues of foundations and framing are addressed. A simple A frame structure allows for easy construction. It also allows snow and rain to slide off greenhouse sides without collapsing the structure.

The Foundation

To build simple greenhouse options, unlike living quarters, you will not need quite as complex a foundation. Your foundation can be as simple as a 2×4 box secured with short wooden posts driven into the ground a few feet, or as complicated as poured concrete with expansion joints. The primary thing to consider is maintaining the structural integrity of your wooden frame. Time can warp and bow wood frames. Wind can lift unsecured structures. Critters can dig through dirt to get into your greenhouse. Think about what it would take to secure your structure, keep it in place, resist warping or bowing, and keep out the critters.

The easiest foundation for a novice is to drive posts into the ground at each corner of the floor and at 2-3 foot intervals along the sides of your build. Simple greenhouse designs really do not need super foundations like houses, so exacting science is not necessary. Finish by nailing 2x4s to the posts to create a box, anchored to the ground by the posts. You can use galvanized framing angles to help secure corners and prevent them from bowing and separating.

Building the Frame

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